CMS 1500 Form Instructions: Detailed Guide for Blocks 28-32b in Ambulance Billing

Accurately completing the CMS 1500 claim form is crucial for healthcare providers, especially in ambulance billing, to ensure timely and correct reimbursement. This detailed guide focuses specifically on Blocks 28 through 32b, addressing common challenges and providing updated instructions to help ambulance billing professionals navigate these critical fields. Understanding each block’s requirements is essential to avoid claim rejections and streamline your billing process.

Block 28 – Total Charge on CMS 1500 (Ambulance Billing)

Block No.: 28 | Block Name: Total Charge | Block Code: LB

Do not complete this block. For most electronic claims submissions, particularly in ambulance billing, the total charge for all services rendered on the claim form is automatically calculated and transmitted through electronic data interchange (EDI). Manually entering information here can lead to discrepancies or rejections, as the payer system expects this field to be blank or automatically populated. Always refer to your specific payer guidelines and the latest official CMS instructions for the CMS 1500 form for confirmation.

Block 29 – Amount Paid on CMS 1500 (Ambulance Billing)

Block No.: 29 | Block Name: Amount Paid | Block Code: A

This block is used to report any payments received from the patient or on their behalf at the time of service, before the claim is processed by the primary payer. It is critical to distinguish between different types of patient contributions:

• Patient Pay (CAO/PA 162RM): If a patient is responsible for a specific portion of their medical bills as determined by a local County Assistance Office (CAO), this amount should be entered here. This typically applies when notification is officially received from the local CAO on a **PA 162RM form**. This specific patient responsibility is often a result of state-specific programs or financial assistance determinations.
• Copayments and Deductibles: Do not enter general copayments or deductibles in this block. These amounts are typically collected later or are determined after the primary payer processes the claim and are reflected on the Explanation of Benefits (EOB) or Remittance Advice (RA). Entering them here prematurely can lead to incorrect claim adjudication.

Ensure that any amount entered in Block 29 is accurately documented and can be supported by patient records and relevant CAO notifications. Incorrect entries can cause delays or claim rejections.

Block 30 – Balance Due on CMS 1500 (Ambulance Billing)

Block No.: 30 | Block Name: Balance Due | Block Code: LB

Do not complete this block. Similar to Block 28 (Total Charge), the balance due for a claim is typically calculated automatically by the payer’s system during electronic claim processing. This field is generally left blank for most ambulance claims submitted electronically. Attempting to manually populate this field can override system calculations and potentially lead to processing errors or claim rejections. Adhere to the latest official CMS 1500 claim form instructions.

Block 31 – Signature of Physician or Supplier Including Degree or Credentials (Ambulance Billing)

Block No.: 31 | Block Name: Signature of Physician or Supplier Including Degree or Credentials | Block Code: M/M

This block requires the signature of the provider who rendered the service or their authorized representative. The signature serves as a certification that the services were medically necessary and performed as described. Understanding current requirements is vital, especially given the evolution of electronic health records and claim submissions:

• Manual Signatures: A legible, handwritten signature or a signature stamp is generally acceptable, provided the provider explicitly authorizes its use and assumes full responsibility for the accuracy of the claim information. This does not apply to specific exceptions like abortions, where manual signatures might be mandated.
• Electronic Signatures: For computer-generated or electronic claims (EDI submissions), this block can often be left blank on the physical form. However, this does not negate the signature requirement. Providers must have a legally binding electronic signature on file or an authenticated electronic submission process in place that complies with **CMS signature requirements** and other federal regulations like HIPAA. The outdated “Signature Transmittal Form (MA 307)” is rarely the primary method today; modern systems use digital authentication.
• Date of Submission: The date the claim was submitted should be entered here in an 8-digit MMDDCCYY format (e.g., 01012024 for January 1, 2024). This must reflect the current submission date, not an outdated example from previous years.

The signature implies legal certification of the claim’s accuracy and compliance. Always consult the most current CMS guidance on electronic signatures and claim submissions, as requirements can change frequently. You may also find our **article on proper medical record documentation** helpful.

Block 32 – Service Facility Location Information on CMS 1500 (Ambulance Billing)

Block No.: 32 | Block Name: Service Facility Location Information | Block Code: LB

Do not complete this block. For ambulance services, the “service facility location” is often mobile or refers to the point of patient pickup, which is not a fixed facility in the traditional sense. In most ambulance billing scenarios, this information is typically captured and transmitted through other claim data fields or is inferred from the nature of the service itself. Entering redundant or incorrect information in this block can lead to claim processing issues. Always ensure your electronic submission system accurately conveys the service location details.

Block 32a – NPI of Service Facility Location

Block No.: 32a | Block Name: N/A | Block Code: LB

Do not complete this block. This field, often associated with Block 32, is generally left blank for ambulance claims. The information typically required here for other medical services (e.g., facility NPI) is usually not applicable or is handled differently for mobile ambulance services.

Block 32b – N/A (Other Facility Information)

Block No.: 32b | Block Name: N/A | Block Code: LB

Do not complete this block. Similar to Block 32a, this field is typically not completed for ambulance services. Detailed facility information is usually not required in these specific blocks for emergency or non-emergency medical transport claims, as the service is rendered in transit or at a patient’s location.

Quick Reference Table for CMS 1500 Blocks 28-32b (Ambulance Billing)

Mastering the intricacies of the CMS 1500 form, particularly for specialized services like ambulance billing, is fundamental to financial success in healthcare. By diligently adhering to the instructions for Blocks 28-32b and staying informed about the latest CMS and payer-specific guidelines, billing professionals can significantly reduce claim errors and ensure efficient reimbursement. Always consult official documentation and specific payer manuals for the most accurate and up-to-date requirements.